Magneto



A. H. HYNDMAN.

MAGNETO.

APPLICATION FILED NOV. 16, 1918.

Patented Feb. 21, 1922.

2 SHEETSSHEET I.

r m e m A. H. HYNDMAN.

MAGNETO. APPLICATION FILED NOV. 16, 1918.

1,407,421, Patented Feb. 21, 1922.

2 SHEETS-SHEET 2- Emmi)? having for its axis the axis of the armature. The inner faces are plane faces which abut against and cover the ends of the core 17. The pole pieces over-hang the core 17 on all sides. The shaft 10, core 17 and pole pieces 1'8 and 19 are preferably all secured together by a pin or rod 20 which extends through holes drilled through these parts, and is riveted at its ends to the pole pieces 18 and 19. The holes in the latter through which the rod passes are preferably countersunk, so that when the ends of the rod 20 are struck up so as to provide the rivet heads, none of the metal of the rod will extend beyond the cylindrical faces of the pole pieces. In the present instance, I also provide two screws 21 for further securing the pole piece 18 to the core 17. Screws 22 perform a like function for the pole piece 19. All of these screws pass into threaded en gagement with openings in the ends of the core 17. The openings in the pole pieces through which they pass are counter-sunk so that the top of the screw lies flush with the cylindrical surface of the pole pieces. In order to prevent each screw from working loose, I preferably drill a small hole through the head of the screw and into the pole piece and drive a small pin into the same as indicated at 23 in Figs. 1 and 2. Obviously, the pole pieces, core and shaft might be connected differently than I have illustrated. Thus, in certain instances, the screws 21 and 22 might be omitted and the riveted rod 20 relied upon to hold the parts together. In other instances, the screws might be employed and the rod might be omitted, and in still other instances, the

core and shaftmight be connected together.

by other means. 7

In the form of the invention under consideration, two sets of windings are employed. These are in the forms of coils 24 and 25 which occupy the space between the shaft 10 and the overhanging portions of the pole pieces 18 and 19, respectively. Obviously, these windings may be wound upon the core 17 after the pole pieces have been secured in place. The turns of insulated'wire are separated from the adjacent portions of the pole pieces, core and shaft by insulation, the insulation 26 serving in the case of coil 24, and the insulation 27 serving in the case of coil 25. Although the windings may be wound in this way, yet I prefer to make each of the coils a separate unitary structure which may be wound independently of the other parts of the armature and kept in stock for assembling with the other parts in the original manufacture or for replacing defective coils when the armature needs repair. Such a unitary coil is shown in Fig. 4, where the winding 24 is located upon insulation 26, which has the form of a spool. These units can be made up in various ways, as by winding the insulated conductor upon forms and then placing the completed coil upon the shank of the spool of insulating material and then applying either or both of the end flanges of the spool, or the coils may be wound either independently of the spool or upon it by suitable winding machines. The terminals of the coils 24 and 25 may be connected in any suitable way, thus for example, the one terminal may be connected to the collecting ring 15, as indicated at 28, and the other may be connected to some portion of the iron structure of the armature such as the pole piece 18, as indicated at 29. The coils themselves may obviously be connected together in series or in multiple. These various connections are well known and need not be further gone into in this description.

In case it becomes necessary to replace one of the windings of the armature just described, it is merely necessary to remove the adjacent pole piece, disconnect the terminals of the coil, withdraw the coil from the core, place the new coil in position, restore the pole piece and connect the coil terminals in circuit. In removing the pole piece it will be necessary to destroy the rivet head of the rod 20 so as to drive the rod out and it will also be necessary to free the screws which pass through the pole piece. The latter can be done by drilling out the pin 23. Likewise, the head of the rod 20 may be removed by drilling.

From this description it will be seen that the pole pieces 18 and 19 are removable from the core 17 and yet they are not so readily removable that they can be dislodged or loosened under the continued rotation of the armature nor by simple manipulation on the part of the user. They can, however, be removed by a repair man without much difficulty. The construction provides a considerable advantage in this respect because the coils can be so readily removed and new ones put back into place. By having the coils upon independent spools and in stock it is not necessary to take the time of a workman to unwind the wire of the defective coil and then wind the wire of the new coil on the core. It will be noted that in this construction the polar extensions formed by the over-hanging portions of the pole pieces 18 and 19 serve to hold the coils 24 and 25 in place against any tendency to be dislodged by centrifugal force.

Obviously either the core or pole pieces or both the core and pole pieces may consist of laminations of soft iron instead of consisting of solid pieces as heretofore described. In Fig. 5, I have illustrated a core 30 which is made up of laminations held together by riveting rods, of which one, designated 31, is shown. In this instance, the pole piece is made up of solid ends 32 and intervening lamina-tions 38 which are he d together by transverse riveting rods. one of which, designated is shown. he pole pieces armature and shaft are all secured together by a rod 35 and the pole piece and core are further secured together by screws 36. This structure is similar to that shown in 2 but differs in the employment of laminations instead of solid metal. The illustration of 5 is fragmentary but is sufii cient to illustrate the substitution of a laminated structure for the solid structure.

As a further modification I may cut away a portion of the shaft on either side and also cut away a portion of the under face of each of the pole pieces, all of which is to provide a greater space for the windings of the associated electric coils. Such a modification will be suificiently illustrated by Fig. 6 wherein the shaft 36 is shown cut away on its upper and lower faces and the pole pieces 37 and 38 are shown cut away on their inner faces. These parts are the same as the corresponding parts of Fig. 1 except for the modifications mentioned. In this instance the space between the shaft 36 and the over-hanging portions of the pole piece 37 are occupied by coils 39 and 4:0. buitable insulation 41 separates these coils from each other and from the adjacent portions of the shaft, core and pole piece. In this instance the core 42 is the same the core 17 except that it is provided with a differently shaped opening for the passage of shaft 36. Similar coils 13 and 44, provided with insulation &5, are positioned between the shaft 36 and the pole piece 38. These coils may be variously connected and particular connections need not he specified. With this arrangement the place available for the electric windings of the coils is greater than in the form of the invention illustrated in Figs. 1 and 2 and yet the cylin drical faces of the pole pieces 37 and 38 remain the same in superficial extent.

The shape of the pole piece may be still further modified by constructing the same out of a piece of thin light magnetic material, preferably arcuate in form. Such construction is illustrated in Fig. 7 in the pole piece 46. In this figure also, I have shown the core 47 as composed of laminations connected by riveting rods l8. In this instance the end of the core s7 is curved to conform to the inner face of the pole piece 46, and the pole piece and core are secured together in any suitable way as by the screw 49. The members 50 are sheets of metal provided with central perforations and slipped over the core. They cooperate with the pole piece 46 to provide space for the electric windings 51. These windings are separated from the pole piece 46, core 4-7 and member 50 by suitable insulation. Obviously in this constiaction the core 7 might consistof solid piece of magnetic material the same as in the form of the invention illus trated in Figs. 1 and 2. In this instance, the space provided for the coil 51 is very la and the superficial area of the pole pieces is not decreased.

In still other instances, the capacity of the magneto may be such as to require an increased winding space and an increased magnetic circuit. In such instances. I may i11- crease the ca; city by multiplying the structure of l and 2 so as to provide a plurality of cores with their pole pieces and wind- Such a structure is illustrated in Fig. 8 wherein the shaft is provided with cores )6 5aand of the same construction as shown in Figs. 1 and 2. In this instance the core is orovided with energizing coils and 57 while the core 55 is provided with similar coils 5S and 59. In this instance, the two cores are provided with common pole pieces (30 and 61 and the parts are secured together by rods (32 and 68 and screws or and (35 in a manner similar to that disclosed with reference to l igs. 1 and 2. In this instance the insula'ion about the coils is designated by the numerals 66, 67, 68 and (39.

In still other forms of the invention. the

journals 70 and 71 of the armature may be directly secured to heads 72 and 73 which are in turn secured tothe opposite ends of pole )lQCGS 74 and 75 while the latter are secured to the opposite ends of a core 76. In this instance, it will be seen that the core has no direct connection with the armatureshaft but the latter is divided in the manner illustrated. In this instance, the core 76 is connected with the pole pieces 74% and 75 by a rod 77 and screws 78 and 79 in the manner heretofore described. In this instance the heads 7 2 and 7 3 are secured to the pole pieces 7% and 75 by pins 80, 81, 82 and 83 which extend through openings in the' heads into engagement with holes tapped into the ends of pole pieces. In this form of the invention, the windings lill the entire space between the pole pieces H and 75 around the core 7 (3. In the present instance.

an inner coil 84- and an outer coil '85 with if suitable insulation 86 intervening and separating the coils from the pole pieces and core, constitute the windings. A suitable electric terminal is provided by a pin 87 riveted to the center of a spring plate 88 which is seone terminal of the coil 85 is shown soldered to the head '73 at the point 89*- and the other to theplate 88 at 90. Such a connection will sufiice where the windings of coils 84.- and 85 are primary ant secondary windings respectively.

As illustrative of modified connecting means between the pole pieces and core, I have added Fig. 11 wherein the core 1? and pole piece 18 of Fig. 2 are illustrated in connection with a rod 91 which extends through them and the connecting shaft as in Fig. 2 but which instead of being riveted as in Fig. is electrically welded by the deposition oi .netal as indicated at 92 where the electrically de posited welding metal is shown in a socket or counter-sunk opening. As. there shown, it does not extend beyond the face of the pole piece 18. Obviously, other connecting means might be employed for securing these various parts together with sufficient certainty to guarantee their remaining in position until taken in hand by the repair man. iiiirewise, in these constructions, the core may be greatly varied in cross-sectional shape. ()1 viously too, the windings upon the armature may in many instances be primary and secondary windings variously connected and associated. The construction provided retains all the advantages possessed by prior art devices in respect to the electrical con nections of the various windings of the coils. I may also point out that other means may be employed for holding the screws in the pole piece against rotation than the pins 23 heretofore described. Such means may be in addition to or a substitute for these pins. In the form of the invention illustrated in hi 1, such additional means are provided by the heads of the rod 20. The countersinlrs pro vided at the ends of the hole for the rod 2) and those provided for the screws 21 and are made to overlap. By countersinking the holes for the rod after the screws are set. a

portion of the head of each screw cut away. Then when the end of the rod 18 welded or riveted, the metal of the rivet transversely apertured core of magnetic materiai, a shaft extending through and closely fitting within the aperture in said core, the axes of said core and said shaft intersecting each other at right angles, the shaft having flat portions on its opposite sides and on opposite sides of and close to said core, said portions lying in parallel planes perpendicular to the axis of said core, pole pieces of magnetic material secured to the opposite ends of said core and overhangingthe same on all sides and having in each instance an outer cylindrical surface and a plurality of inner plane faces lying in planes parallel to the flat portions of said shaft, said inner plane faces on each pole piece con'iprising a central face contiguous to the core and a peripheral ace more distant therefrom, the central faces of both pole pieces being coextensive in superficial area and lying equidistant from said shaft and farther therefrom than the peripheral faces, and two electric coils fitting closely about said core on opposite sides of said shaft and completely filling in each instance the space between the central inner face on the pole piece and the cooperating flat portion on the shaft, said pole pieces being removable from said core to allow said coils to be removed as units from said core.

2. A magneto armature comprising a transversely apertured core of magnetic material, a shaft extending through and closely fitting within the aperture in said core. the axes of said core and said shaft intmsectin; each other at right angles, pole pieces of magnetic material secured to the opposite ends of said core and overhanging the same on all sides and having in each instance an outer cylindrical surface and a plurality of inner plane faces lying in parallel planes perpendicular to the axis of said core, said inner plane faces on each pole piece comprising a central face contiguous to said core and a peripheral face more distant therefrom, the central faces of both pole pieces being of the same superficial area and lying equidistant from said shaft and farther therefrom than the peripheral faces, and two electric coils closely fitting about said core on opposite sides of said shaft and completely filling in each instance the space between the shaft and the central face of the pole piece. said pole pieces being removable to allow said coils to be removed as units from said core.

In testimony whereof, I hereunto subscribe my name this 14th day of November. 1918.

ALEXANDER H. HYNDMAN. 

